1. Field of the Invention
The present invention relates to a motor device, more particularly relates to an improvement of a motor device for directly rotating for example a 3.5 inch flexible disk.
2. Description of the Related Art
In the past, as the motor device for directly supporting and rotating a 3.5 inch flexible disk etc., as shown in FIG. 4, there has been known a spindle configuration directly fastening a radial bearing 3 comprised of for example an oil-less metal by press fitting to a magnetic material stator plate 1 forming a not shown electronic circuit, placing a thrust bearing 5 comprised of hard balls 5a held by a retainer 5b gripped between thrust receiving plates 5c and 5d so as to be fit at the outer circumference of the radial bearing 3, fastening a plurality of drive coils 7 flat against the stator plate 1 so as to surround the thrust bearing 5, axially supporting the rotor shaft 11 holding the rotor plate 9 at the radial bearing 3, making the rotor plate 9 abut with the thrust receiving plate 5d, and making a drive magnet 13 fastened to the rotor plate 9 face the drive coils 7.
The motor drive of this configuration has the rotor shaft 11 supported by the radial bearing 3 in the radial direction and has the rotor plate 9 rotating in the state supported by the thrust bearing 5 in the thrust direction, so if holding the flexible disk by a not shown known holding method at the back surface of the rotor plate 9, this can be made to rotate.
Summarizing the problems to be solved by the invention, the motor device of the above configuration has the radial bearing 3 axially supporting the rotor shaft 11 directly fastened to the stator plate 1 by press fitting, so particularly the stator plate 1 easily warps due to the pressure at the time of press fitting, the axial center of the rotor shaft 11 tilts and rotational vibration occurs, the motor itself is attached to the electronic apparatus at a tilt, and accurate planar rotation of the flexible disk can no longer be secured.
Further, as shown by the broken lines in FIG. 5, the magnetic material stator plate 1 easily deforms due to attraction of the drive magnet 13 fastened to the rotor plate 9, the radial bearing 3 also displaces so that the axial center of the rotor shaft 11 tilts, and accurate planar rotation of the flexible disk becomes hard to secure.
An object of the present invention is to provide a motor device suppressing tilting of the rotor shaft and improving resistance to rotational vibration without enlarging the thickness dimension in the rotor shaft direction.
To achieve the above object, there is provided a motor device comprising a stator unit of a motor having a stator plate; a rotor unit of the motor; a thrust bearing for receiving pressure in a thrust direction of the rotor unit and securing rotation of the rotor unit and securing rotation of that rotor unit; and an auxiliary support plate on which a thrust receiving plate of the stator unit side in that thrust bearing of the stator unit side in the thrust bearing is placed and supporting the thrust bearing at the stator unit.
The auxiliary support plate has a flange formed at a region outside from the thrust receiving plate and formed bent in an axial direction of the rotor unit side. The region inside of the flange is fit into the stator plate, so the flange is placed on the stator plate facing the rotor unit and supported by the same.
Preferably, the auxiliary support plate is formed by a material harder than the stator plate.